Tobacco-derived filter element

ABSTRACT

A filter material adapted for use as a filter element of a smoking article is provided, the filter material including at least 10 dry weight percent of cellulosic pulp derived from stalks, roots, or a combination thereof of a plant of the  Nicotiana  species, wherein the filter material is in the form of a paper comprising the cellulosic pulp or a fibrous tow comprising the cellulosic pulp in esterified form. Filter elements and smoking articles, such as cigarettes, that contain the filter material are also provided. Methods of preparing filter materials for use in filter elements are also provided.

FIELD OF THE INVENTION

The present invention relates to tobacco products, such as smoking articles (e.g., cigarettes), and in particular, to filters for cigarettes. The invention is directed to tobacco-derived materials that can be useful as a filtration media.

BACKGROUND OF THE INVENTION

Popular smoking articles, such as cigarettes, have a substantially cylindrical rod-shaped structure and include a charge, roll or column of smokable material, such as shredded tobacco (e.g., in cut filler form), surrounded by a paper wrapper, thereby forming a so-called “smokable rod” or “tobacco rod.” Normally, a cigarette has a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Typically, a filter element comprises plasticized cellulose acetate tow circumscribed by a paper material known as “plug wrap.” Typically, the filter element is attached to one end of the tobacco rod using a circumscribing wrapping material known as “tipping paper.” It also has become desirable to perforate the tipping material and plug wrap, in order to provide dilution of drawn mainstream smoke with ambient air. Descriptions of cigarettes and the various components thereof are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999). A cigarette is employed by a smoker by lighting one end thereof and burning the tobacco rod. The smoker then receives mainstream smoke into his/her mouth by drawing on the opposite end (e.g., the filter end) of the cigarette.

The discarded portion of the cigarette rod is primarily composed of the filter element, which typically consists of tightly-compacted and highly crimped cellulose acetate fibers bonded at their contact points and wrapped by the a plug wrap and tipping paper. The presence of the wrapping materials, the fiber-to-fiber bonding, and the compacted nature of conventional filter elements has a detrimental effect on the rate of degradation of cigarette filters in the environment. Unless the filter element is unwrapped and the fibers spread apart to increase exposure, biodegradation of the filter can take several years.

A number of approaches have been used in the art to promote an increased rate of degradation of filter elements. One approach involves incorporation of additives (e.g., water soluble cellulose materials, water soluble fiber bonding agents, photoactive pigments, or phosphoric acid) into the cellulose acetate material in order to accelerate polymer decomposition. See U.S. Pat. No. 5,913,311 to Ito et al.; U.S. Pat. No. 5,947,126 to Wilson et al.; U.S. Pat. No. 5,970,988 to Buchanan et al.; and U.S. Pat. No. 6,571,802 to Yamashita. In some cases, conventional cellulose acetate has been replaced with other materials, such as moisture disintegrative sheet materials, extruded starch materials, or polyvinyl alcohol. See U.S. Pat. No. 5,709,227 to Arzonico et al; U.S. Pat. No. 5,911,224 to Berger; U.S. Pat. No. 6,062,228 to Loercks et al.; and U.S. Pat. No. 6,595,217 to Case et al. Incorporation of slits into a filter element has been proposed for enhancing biodegradability, such as described in U.S. Pat. No. 5,947,126 to Wilson et al. and U.S. Pat. No. 7,435,208 to Garthaffner. U.S. Pat. No. 5,453,144 to Kauffman et al. describes use of a water sensitive hot melt adhesive to adhere the plug wrap in order to enhance biodegradability of the filter element upon exposure to water. U.S. Pat. No. 6,344,349 to Asai et al, proposes to replace conventional cellulose acetate filter elements with a filter element comprising a core of a fibrous or particulate cellulose material coated with a cellulose ester to enhance biodegradability. Still further, U.S. Pat. No. 8,434,498 to Sebastian suggests addition of starch particles to cellulose acetate fibers for purposes of increasing biodegradability of cigarette filters, US Pat. App. Publ. No. 2012/0000477 to Sebastian et al. suggests use of degradable adhesives for smoking article wrapping materials, US Pat. App. Publ. No. 2013/0025610 to Sebastian et al. suggests plasticizers for biodegradable filter elements, and US Pat. App. Publ. Nos. 2013/0074853 to Sebastian et al., 2014/0026909 to Sebastian, and 2014/0096783 to Sebastian et al. describe various techniques for forming fiber blends with enhanced biodegradability.

There remains a need in the art for a smoking article filter exhibiting enhanced environmental degradation properties.

SUMMARY OF THE INVENTION

The present invention relates to a smoking article, and in particular, a rod-shaped smoking article (e.g., a cigarette). The smoking article includes a lighting end (i.e., an upstream end) and a mouth end (i.e., a downstream end). A mouth end piece is located at the extreme mouth end of the smoking article, and the mouth end piece allows the smoking article to be placed in the mouth of the smoker to be drawn upon. The mouth end piece has the form of a filter element comprising a filter material. The filter material can comprise at least 10 dry weight percent, or at least 20 dry weight percent of cellulosic pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species. Furthermore, the filter material can be in the form of a paper comprising the pulp or a fibrous tow comprising the pulp in esterified form.

In various embodiments, the filter material can be in the form of a paper that is pleated or fluted to form a rod-like element. The web of sheet-like material can have a basis weight of about 20 gsm to about 90 gsm.

In some embodiments, a filter element for a smoking article can include one or more segments of a filter material comprising at least 10 dry weight percent, or at least 20 dry weight percent of cellulosic pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species, wherein the filter material can be in the form of a paper comprising the pulp or a fibrous tow comprising the pulp in esterified form. In some embodiments, a cigarette comprising a tobacco rod having a smokable filler material contained within a circumscribing wrapping material and a filter element connected to the tobacco rod at one end of the tobacco rod can be provided, wherein the filter element includes at least one segment of a filter material according to the present invention.

The present invention further provides a method for formation of a filter element of a smoking article, the method comprising: i) pulping a tobacco input comprising stalks, roots, or a combination thereof of a plant of the Nicotiana species to form a cellulosic pulp; ii) forming a web of sheet-like material comprising the cellulosic pulp; and iii) pleating the web of sheet-like material to form a rod-like element suitable for use in a filter element. In some embodiments, the web of sheet-like material can have a basis weight of about 20 gsm to about 90 gsm. In various embodiments, the web of sheet-like material can comprise at least 10 dry weight percent, or at least 20 weight percent of the cellulosic pulp. In certain embodiments, the rod-like element can be adapted for use as a filter element in a smoking article.

Also provided herein is a method for formation of a filter element of a smoking article, the method comprising: i) pulping a tobacco input comprising stalks, roots, or a combination thereof of a plant of the Nicotiana species to form a cellulosic pulp; ii) esterifying the cellulosic pulp to produce cellulose acetate; iii) dissolving the cellulose acetate in a solvent to form a cellulose acetate dope; iv) spinning the cellulose acetate dope into a plurality of filaments; and v) collecting, drying and crimping the plurality of filaments to form a tow material suitable for use in a filter element, the tow material comprising at least 10 dry weight percent, or at least 20 dry weight percent of cellulose acetate filaments made from the cellulosic pulp. In certain embodiments, the method can further comprise blending the tow material with ethyl cellulose fibers, cellulose acetate-lignin blended fibers, or a combination thereof to form a biodegradable blend of filter tow material suitable for use in a filter element.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to assist the understanding of embodiments of the invention, reference will now be made to the appended drawings, which are not necessarily drawn to scale. The drawings are exemplary only, and should not be construed as limiting the invention.

FIG. 1 is an exploded perspective view of a smoking article having the form of a cigarette, showing the smokable material, the wrapping material components, and the filter element of the cigarette;

FIG. 2 is a cross-sectional view of an embodiment of a filter element according to the invention; and

FIG. 3 is a cross-sectional view of another embodiment of a filter element according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present inventions now will be described more fully hereinafter with reference to the accompanying drawing. The invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. As used in this specification and the claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

As described herein, embodiments of the disclosure relate to filter materials comprising tobacco-derived cellulosic pulp and to methods for producing filtration media from tobacco, and related systems, apparatuses, and products. In this regard, the tobacco-derived filtration materials can be employed, for example, in tobacco products suitable for oral use. Traditional cigarette filter materials include cellulose acetate tow, gathered cellulose acetate web, polypropylene tow, gathered cellulose acetate web, gathered paper, strands of reconstituted tobacco, or the like. However, cellulose acetate can be slow to degrade. Accordingly, as discussed in more detail below, the present invention provides biodegradable filter materials that at least partially include cellulosic pulp derived from a plant of the Nicotiana species.

Pulp is conventionally produced from wood or other cellulose materials. However, as described herein, it can be desirable to instead produce pulp derived from alternative sources, such as, for example, tobacco. In some embodiments the tobacco input can comprise one or more components from a plant of the Nicotiana species including leaves, seeds, flowers, stalks, roots, and/or stems. For example, as described below, in some embodiments the tobacco input can comprise flue-cured tobacco stalks, burley tobacco stalks, and/or whole-plant tobacco biomass (e.g., extracted green tobacco biomass). It can be advantageous to use roots, stalks, or a combination thereof from a plant of the Nicotiana species due to the relatively high portion of cellulose fibers in these parts of the plant.

Cellulose is understood to be a polysaccharide of the formula (C₆H₁₀O₅)_(n), wherein n can be a number from about 10 to over 10,000. In plants (e.g., plants of the Nicotiana species), cellulose is commonly found in a mixture with hemicellulose, lignin, pectin, and other substances. For example, analysis of green tobacco stalks has revealed the presence of cellulose, hemi-cellulose, lignin, pectin, and sugars.

The tobacco stalks and/or roots can be separated into individual pieces (e.g., roots separated from stalks, and/or root parts separated from each other, such as big root, mid root, and small root parts) or the stalks and roots may be combined. By “stalk” is meant the stalk that is left after the leaf (including stem and lamina) has been removed. “Root” and various specific root parts useful according to the present invention may be defined and classified as described, for example, in Mauseth, Botany: An Introduction to Plant Biology: Fourth Edition, Jones and Bartlett Publishers (2009) and Glimn-Lacy et al., Botany Illustrated, Second Edition, Springer (2006), which are incorporated herein by reference. The harvested stalks and/or roots are typically cleaned, ground, and dried to produce a material that can be described as particulate (i.e., shredded, pulverized, ground, granulated, or powdered).

Although the tobacco material may comprise material from any part of a plant of the Nicotiana species, the majority of the material advantageously comprises material obtained from the stalks and/or roots of the plant. For example, in certain embodiments, the tobacco material comprises at least about 80%, at least about 90%, at least about 95%, or at least about 99% by dry weight of at least one of the stalk material and the root material of a harvested plant of the Nicotiana species.

Where the method employs stalks, entire stalks or only portions of the stalks may be used in the process. The stalks may be directly processed in harvested form or may be physically altered by shredding or chopping prior to pulping. As an alternative, the tobacco stalks may be prepared using a method by which the fibrous structure of the stalk rind surrounding the pith is used and the pith itself is isolated for another purpose. For example, a splitter device can be used to separate the rind from the pith. See, for example, U.S. Pat. Nos. 3,424,611, 3,424,612, and 3,464,877 to Miller et al.; U.S. Pat. No. 4,151,004 to Vukelic; and U.S. Pat. Nos. 3,567,510, 3,976,498, and 4,312,677 to Tilby et al., each of which is incorporated herein by reference. These references describe splitting methods to separate sugar cane into its individual parts, which may be adapted for use with tobacco stalks in accordance with the present invention. Thus, in some embodiments, only the separated rind (rather than the entire tobacco stalk itself) is processed as provided herein. It is to be understood that reference to processing “stalks” is also intended to encompass processing portions of stalks, e.g., separated rind components.

The selection of the plant from the Nicotiana species (i.e., tobacco material) utilized in the products and processes of the invention can vary; and in particular, the types of tobacco or tobaccos may vary. Tobaccos that can be employed include flue-cured or Virginia (e.g., K326), burley, sun-cured (e.g., Indian Kurnool and Oriental tobaccos, including Katerini, Prelip, Komotini, Xanthi and Yambol tobaccos), Maryland, dark, dark-fired, dark air cured (e.g., Passanda, Cubano, Jatin and Bezuki tobaccos), light air cured (e.g., North Wisconsin and Galpao tobaccos), Indian air cured, Red Russian and Rustica tobaccos, as well as various other rare or specialty tobaccos. Descriptions of various types of tobaccos, growing practices and harvesting practices are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999), which is incorporated herein by reference. Various representative types of plants from the Nicotiana species are set forth in Goodspeed, The Genus Nicotiana, (Chonica Botanica) (1954); U.S. Pat. No. 4,660,577 to Sensabaugh, Jr. et al.; U.S. Pat. No. 5,387,416 to White et al.; U.S. Pat. No. 7,025,066 to Lawson et al.; and U.S. Pat. No. 7,798,153 to Lawrence, Jr.; each of which is incorporated herein by reference. Tobacco compositions including dark air cured tobacco are set forth in U.S. Pat. No. 8,186,360 to Marshall et al., which is incorporated herein by reference. See also, types of tobacco as set forth, for example, in US Patent Appl. Pub. No. 2011/0247640 to Beeson et al., which is incorporated herein by reference.

Exemplary Nicotiana species include N. tabacum, N. rustica, N. alata, N. arentsii, N. excelsior, N. forgetiana, N. glauca, N. glutinosa, N, gossei, N. kawakamii, N. knightiana, N. langsdorffi, N. otophora, N. setchelli, N. sylvestris, N. tomentosa, N. tomentosiformis, N. undulata, N. x sanderae, N. africana, N. amplexicaulis, N. benavidesii, N. bonariensis, N. debneyi, N. longiflora, N. maritina, N. megalosiphon, N. occidentalis, N. paniculata, N. plumbaginifolia, N. raimondii, N. rosulata, N. simulans, N. stocktonii, N. suaveolens, N. umbratica, N. velutina, N. wigandioides, N. acaulis, N. acuminata, N. attenuata, N. benthamiana, N. cavicola, N. clevelandii, N. cordifolia, N. corymbosa, N. fragrans, N. goodspeedii, N, linearis, N. miersii, N. nudicaulis, N. obtusifolia, N. occidentalis subsp. Hersperis, N. pauciflora, N. petunioides, N. quadrivalvis, N. repanda, N. rotundifolia, N. solanifolia and N. spegazzinii.

Nicotiana species can be derived using genetic-modification or crossbreeding techniques (e.g., tobacco plants can be genetically engineered or crossbred to increase or decrease production of components, characteristics or attributes). See, for example, the types of genetic modifications of plants set forth in U.S. Pat. No. 5,539,093 to Fitzmaurice et al.; U.S. Pat. No. 5,668,295 to Wahab et al.; U.S. Pat. No. 5,705,624 to Fitzmaurice et al.; U.S. Pat. No. 5,844,119 to Weigl; U.S. Pat. No. 6,730,832 to Dominguez et al.; U.S. Pat. No. 7,173,170 to Liu et al.; U.S. Pat. No. 7,208,659 to Colliver et al. and U.S. Pat. No. 7,230,160 to Benning et al.; US Patent Appl. Pub. No. 2006/0236434 to Conkling et al.; and PCT WO 2008/103935 to Nielsen et al. See, also, the types of tobaccos that are set forth in U.S. Pat. No. 4,660,577 to Sensabaugh, Jr. et al.; U.S. Pat. No. 5,387,416 to White et al.; and U.S. Pat. No. 6,730,832 to Dominguez et al., each of which is incorporated herein by reference.

Further, in some embodiments the tobacco input can comprise reconstituted tobacco. Typically, tobacco stems are used in making such a reconstituted tobacco sheet, because the fibrous nature of those stems provides strength and structural integrity to the resulting sheet. See, for example, U.S. Pat. No. 3,398,754 to Tughan; U.S. Pat. No. 3,847,164 to Mattina; U.S. Pat. No. 4,131,117 to Kite; U.S. Pat. No. 4,182,349 to Selke; U.S. Pat. No. 4,270,552 to Jenkins; U.S. Pat. No. 4,308,877 to Mattina; U.S. Pat. No. 4,341,228 to Keritsis; U.S. Pat. No. 4,421,126 to Gellatly; U.S. Pat. No. 4,706,692 to Gellatly; U.S. Pat. No. 4,962,774 to Thomasson; U.S. Pat. No. 4,941,484 to Clapp; U.S. Pat. No. 4,987,906 to Young; U.S. Pat. No. 5,056,537 to Brown; U.S. Pat. No. 5,143,097 to Sohn; U.S. Pat. No. 5,159,942 to Brinkley et al.; U.S. Pat. No. 5,325,877 to Young; U.S. Pat. No. 5,445,169 to Brinkley; U.S. Pat. No. 5,501,237 to Young; and U.S. Pat. No. 5,533,530 to Young, which are incorporated herein by reference.

Production of pulp derived from tobacco can involve a number of operations. In general, pulps can be produced from raw materials either mechanically or chemically, as is known in the art. In a mechanical pulping process, raw tobacco materials can be chipped, and then fed between refiners where the chips are made into fibers between revolving metal disks, for example. For example, mechanical pulping techniques can be used to produce tobacco pulp (i.e., tobacco-derived cellulosic pulp) from raw tobacco stalk, raw tobacco root, or a combination thereof. The raw tobacco input can be pretreated with water and then refined with a plurality of passes through a machine that can chip the tobacco input, for example. See, for example, the machines discussed in U.S. Pat. No. 3,661,192 to Nicholson et al.; U.S. Pat. No. 3,861,602 to Smith et al.; U.S. Pat. No. 4,135,563 to Maucher; and U.S. Pat. No. 5,005,620 to Morey, each of which is incorporated by reference herein. These chipped pulps can then be refined in a mill, for example. See, for example, the methods and apparatuses discussed in U.S. Pat. No. 6,773,552 to Albert et al.; and U.S. Appl. Pub. No. 2010/0036113 to Mambrim Filho et al, which are incorporated by reference herein.

In some embodiments, a chemical pulping process can be used to make a pulp from raw tobacco materials. A chemical pulping process separates lignin from cellulose fibers by dissolving lignin in a cooking liquor such that the lignin, which binds the cellulose fibers together, can be washed away from the cellulose fibers without seriously degrading the cellulose fibers. There are three main chemical pulping processes known in the art. Soda pulping involves cooking raw material chips in a sodium hydroxide cooking liquor. The kraft process evolved from soda pulping and involves cooking raw material chips in a solution of sodium hydroxide and sodium sulfide. The acidic sulfite process involves using sulfurous acid and bisulfate ion in the cook. Any chemical pulping process, including, but not limited to the three examples listed above, can be used to produce a tobacco pulp from raw tobacco materials.

A cooking liquor can comprise a strong base. As used herein, a strong base refers to a basic chemical compound (or combination of such compounds) that is able to deprotonate weak acids in an acid-base reaction. For example, strong bases that can be useful in the present invention include, but are not limited to one or more of sodium hydroxide, potassium hydroxide, sodium sulfide, and combinations thereof. In some embodiments, the weight of the strong base can be greater than about 5%, greater than about 25%, or greater than about 40% of the weight of the tobacco input. Various other chemicals and weight ratios thereof can also be employed to chemically pulp the tobacco input in other embodiments.

In addition to combining a tobacco input with a strong base, chemically pulping a tobacco input can include heating the tobacco input and the strong base. Heating the tobacco input and the strong base can be conducted to increase the efficacy of the chemical pulping. In this regard, an increase in either cooking temperature or time will result in an increased reaction rate (rate of lignin removal).

The method of producing a tobacco-derived pulp can include one or more additional operations in some embodiments. See, e.g., U.S. Patent Appl. Pub. No. 2013/0276801 to Byrd Jr. et al., herein incorporated by reference in its entirety. For example, the tobacco input can undergo further processing steps prior to pulping and/or the pulping method can include additional treatment steps (e.g., drying the tobacco input, depithing the tobacco input, milling the tobacco input, etc.). In some embodiments, these additional steps can be conducted to remove pith (which comprises lignin) from the tobacco input and/or tobacco pulp manually, and thus reduce the amount of chemicals necessary to delignify the tobacco input during a chemical pulping process, for example. Mixing water with the tobacco-derived cellulosic pulp to form a slurry and filtering the slurry can be conducted, for example, to remove some of the non-cellulosic materials, such as pith, parenchyma, and tissue from the tobacco pulp. Additional treatment steps (e.g., milling the tobacco input) can be conducted to increase the surface area of the tobacco input such that the efficacy of a pulping and/or a bleaching operation is increased. Steam- or water-based pre-hydrolysis of the tobacco stalk prior to pulping, for example, can reduce the amount of chemicals necessary in a bleaching operation. Anthraquinone can be employed in a chemical pulping method in an attempt to provide a higher yield by protecting carbohydrates from the strong base during delignification, for example. Other processing steps known in the papermaking art can be employed in pulping the raw tobacco input.

The tobacco pulp can optionally be exposed to a bleaching agent. The bleaching operation can be conducted to remove the residual non-cellulosic materials left over after pulping without damaging the cellulose. Exemplary processes for treating tobacco with bleaching agents are discussed, for example, in U.S. Pat. No. 787,611 to Daniels, Jr.; U.S. Pat. No. 1,086,306 to Oelenheinz; U.S. Pat. No. 1,437,095 to Delling; U.S. Pat. No. 1,757,477 to Rosenhoch; U.S. Pat. No. 2,122,421 to Hawkinson; U.S. Pat. No. 2,148,147 to Baier; U.S. Pat. No. 2,170,107 to Baier; U.S. Pat. No. 2,274,649 to Baier; U.S. Pat. No. 2,770,239 to Prats et al.; U.S. Pat. No. 3,612,065 to Rosen; U.S. Pat. No. 3,851,653 to Rosen; U.S. Pat. No. 3,889,689 to Rosen; U.S. Pat. No. 4,143,666 to Rainer; U.S. Pat. No. 4,194,514 to Campbell; U.S. Pat. No. 4,366,824 to Rainer et al.; U.S. Pat. No. 4,388,933 to Rainer et al.; and U.S. Pat. No. 4,641,667 to Schmekel et al.; and PCT WO 96/31255 to Giolvas, all of which are incorporated by reference herein.

Once a suitable pulp is achieved, the pulp can optionally be refined to modify the surface structure of the fibers. Refining can physically modify fibers to fibrillate and make the fibers more flexible, such that better bonding can be achieved. Additionally, other additives known in the art can be used to alter characteristics of the pulp fibers.

In various embodiments of the present invention, a tobacco pulp can be used to produce a web of sheet-like material (i.e., a paper). As used herein, the term “paper” is meant to include any sheet or board made from a fibrous cellulosic material and encompasses paperboard. In various embodiments, the thickness of paper (i.e., caliper), is expressed in mils or points; however, both one mil and one point are equivalent to 0.001 inches. Density is expressed in mass per unit volume and bulk is the reciprocal of density. The paper filter material disclosed herein has various potential uses in filter elements; however, possible uses of the paper filter material are not limited to the embodiments discussed herein.

There are a variety of paper grades that can be tailored for a particular end use. Exemplary processes for making paper are discussed, for example, in U.S. Pat. No. 2,795,545 to Gluesenkamp; U.S. Pat. No. 3,224,927 to Brown; U.S. Pat. No. 3,253,978 to Bodendorf; U.S. Pat. No. 3,647,684 to Malcolm; U.S. Pat. No. 4,210,490 to Taylor; U.S. Pat. Nos. 4,385,961 and 4,388,150 to Sunder et al.; U.S. Pat. No. 4,643,801 to Johnson; U.S. Pat. No. 4,749,444 to Aktiengesellschaft; U.S. Pat. No. 4,753,710 to Langley et al.; and U.S. Pat. No. 5,071,512 to Bixler et al, all of which are incorporated by reference herein. Various machines known in the art can be used in a papermaking process. Exemplary machines used to make paper are discussed, for example, in U.S. Pat. No. 3,691,010 to Krake; U.S. Pat. No. 4,102,737 to Morton; U.S. Pat. No. 6,248,210 to Edwards et al.; U.S. Pat. No. 7,291,249 to Thoröe-Scherb et al.; U.S. Pat. No. 8,377,262 to Quigley; and U.S. Pat. No. 8,414,741 to Klerelid et al, all of which are incorporated by reference herein.

In various embodiments, the paper material of the present invention can comprise at least 10%, at least 20%, at least 50%, or at least 75% of pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species. In certain embodiments, the paper material can comprise 100% pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species. In some embodiments, the paper material can include a blend of pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species and pulp derived from other cellulose materials such as wood, for example.

In various embodiments of the present invention, a paper material comprising pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species can be used to form a biodegradable filter element useful in a smoking article. As illustrated in FIG. 2, for example, a web of sheet-like material can be passed through a web preforming unit and pleated to form a rod-like element 105 comprising a plurality of pleats 115. See, for example, the filters, apparatuses and methods discussed in U.S. Pat. No. 4,807,809 to Pryor et al., herein incorporated by reference in its entirety. The rod-like element 105 can then be circumscribed with wrapping material 110 thereby forming a continuous rod 100 that can be used as a filter element or a segment of a filter element, for example. The width of the sheet-like material can vary and typically is a width capable of being pleated to form the rod. The total width of the strip employed in providing a desired rod can depend upon factors such as the thickness of the sheet-like material, the number of pleats desired, the nature or character of the pleats produced, the surface character of the material (i.e., a fibrous surface character versus a smooth surface), the porosity of the material, the moisture content of the material, the lubricity properties of the material, the friction characteristics of the web preforming apparatus relative to the sheet-like material, and other such factors. If desired, the tobacco-derived paper material can be embossed.

Several characteristics known in the art can be used to characterize the web of sheet-like material (i.e., paper). Basis weight and caliper are two parameters used to characterize paper. In some embodiments, the basis weights of paper comprising tobacco pulp described herein can range from about 20 to about 90 g/m², about 30 to about 60 g/m², or about 30 to about 45 g/m². The caliper of tobacco paper described herein can range from about 0.01 to about 4.0 mils, or about 0.01 to about 1.0 mils, or about 0.01 to about 0.5 mils, for example.

Preferred sheet-like materials are thin, and have reasonably high tensile strengths, resiliencies and relatively good flexibilities. In particular, it is desirable that the web have a good “hand” to hold a fold but not tear, crinkle, shatter or otherwise break during the folding or pleating process. It is desirable that the modulus of the web be such that pleating readily occurs. In particular, the web should not be so hard that it does not pleat, nor should the web be so soft that rods of poor resiliency are provided. As such, the rod-like element of pleated web can be provided at a high speed and can be enclosed within the outer wrapping material.

As illustrated in FIG. 2, for example, rod 105 has a substantially cylindrical shape and a generally circular cross sectional shape. Preferably, the ends of the rod each form a plane perpendicular to the longitudinal axis thereof. The rod most preferably includes a plurality of longitudinally extending pleats 115 in the web of sheet-like material. The pleated web is contained in a wrapping material 110 such as cigarette paper wrap or paper plug wrap which is formed in a tubular shape around the pleats. Filter rods can be produced using porous or non-porous plug wrap.

In various embodiments of the present invention, a pulp from stalks, roots, or a combination thereof of a plant of the Nicotiana species can be used to produce a fibrous tow material that can be useful as a filter element. The process for making filter elements according to the invention can vary, but a process for making cellulose acetate filter elements typically begins with forming cellulose fibers. See, e.g., U.S. Pat. Pub. No. 2013/0180536 to Sebastian, which is herein incorporated by reference in its entirety. The first step in conventional cellulose acetate fiber formation is esterifying a cellulose material. As discussed above, traditionally wood is used as a cellulose material. However, the present invention utilizes pulp derived from tobacco. The tobacco-derived pulp can be used alone or in combination with pulp derived from other cellulose materials. Cellulose is a polymer formed of repeating units of anhydroglucose. Each monomer unit has three hydroxyl groups available for ester substitution (e.g., acetate substitution). Cellulose esters may be formed by reacting cellulose with an acid anhydride. To make cellulose acetate, the acid anhydride is acetic anhydride. Cellulose pulp is typically mixed with acetic anhydride and acetic acid in the presence of an acid catalyst such as sulfuric acid. The esterification process of cellulose will often result in essentially complete conversion of the available hydroxyl groups to ester groups (e.g., an average of about 2.9 ester groups per anhydroglucose unit). Following esterification, the polymer is typically hydrolyzed to drop the degree of substitution (DS) to about 2 to about 2.5 ester groups per anhydroglucose unit. The resulting product can be produced in flake form that can be used in subsequent processing.

To form a fibrous material, the cellulose acetate is typically dissolved in a solvent (e.g., acetone, methanol, methylene chloride, or mixtures thereof) to form a viscous solution. The concentration of cellulose acetate in the solution is typically about 15 to about 35 percent by weight. Additives such as whitening agents (e.g., titanium dioxide) can be added to the solution if desired. The resulting liquid is sometimes referred to as a liquid “dope.”

The cellulose acetate dope is spun into filaments using a nonwoven fabric melt-spinning technique, which entails extruding the liquid dope through a spinerette. The filaments pass through a curing/drying chamber, which solidifies the filaments prior to collection. The collected fibers are combined into a tow band, crimped, and dried. Conventional crimp ratios are in the range of 1.2 to 1.8. The fibers are typically packaged in bales that are suitable for later use in filter element formation processes.

The process of forming the actual filter element typically involves mechanically withdrawing the cellulose acetate tow from the bale and separating the fibers into a ribbon-like band. The tow band is subjected to a “blooming” process wherein the tow band is separated into individual fibers. Blooming can be accomplished, for example, by applying different tensions to adjacent sections of the tow band or applying pneumatic pressure. The bloomed tow band then passes through a relaxation zone that allows the fibers to contract, followed by passage into a bonding station. The bonding station typically applies a plasticizer such as triacetin to the bloomed fibers, which softens the fibers and allows adjacent fibers to fuse together. The bonding process forms a homogenous mass of fibers with increased rigidity. The bonded tow is then wrapped in plug wrap and cut into filter rods. Cellulose acetate tow processes are set forth, for example, in U.S. Pat. No. 2,953,838 to Crawford et al. and U.S. Pat. No. 2,794,239 to Crawford et al., which are incorporated by reference herein.

In various embodiments, the final cellulose acetate tow can comprise at least 10%, at least 20%, at least 50%, or at least 75% of esterified pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species. In certain embodiments, the cellulose acetate tow can comprise 100% esterified pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species. In some embodiments, the cellulose acetate tow can include a blend of esterified pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species and esterified pulp derived from other cellulose materials such as wood, for example. In certain embodiments, the tow material comprising esterified tobacco pulp can be blended with ethyl cellulose fibers, cellulose acetate-lignin blended fibers, or a combination thereof to form a biodegradable blend of filter tow material suitable for use in a filter element.

Filter element components or segments for filter elements for multi-segment filtered cigarettes typically are provided from filter rods that are produced using traditional types of rod-forming units, such as those available as KDF-2 and KDF-3E from Hauni-Werke Korber & Co. KG. As discussed above, the filter rods of the present invention can comprise a filter material comprising at least 10 dry weight percent of pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species, wherein the filter material is in the form of a paper comprising the pulp or a fibrous tow comprising the pulp in esterified form. Typically, filter material, such as filter tow (i.e., pulp in esterified form), is provided using a tow processing unit. An exemplary tow processing unit has been commercially available as E-60 supplied by Arjay Equipment Corp., Winston-Salem, N.C. Other exemplary tow processing units have been commercially available as AF-2, AF-3, and AF-4 from Hauni-Werke Korber & Co. KG. In addition, representative manners and methods for operating a filter material supply units and filter-making units are set forth in U.S. Pat. No. 4,281,671 to Byrne; U.S. Pat. No. 4,862,905 to Green, Jr. et al.; U.S. Pat. No. 5,060,664 to Siems et al.; U.S. Pat. No. 5,387,285 to Rivers; and U.S. Pat. No. 7,074,170 to Lanier, Jr. et al. Other types of technologies for supplying filter materials to a filter rod-forming unit are set forth in U.S. Pat. No. 4,807,809 to Pryor et al. and U.S. Pat. No. 5,025,814 to Raker; which are incorporated herein by reference.

Referring to FIG. 1, there is shown a smoking article 10 in the form of a cigarette and possessing certain representative components of a smoking article of the present invention. The cigarette 10 includes a generally cylindrical rod 12 of a charge or roll of smokable filler material contained in a circumscribing wrapping material 16. The rod 12 is conventionally referred to as a “tobacco rod.” The ends of the tobacco rod 12 are open to expose the smokable filler material. The cigarette 10 is shown as having one optional band 22 (e.g., a printed coating including a film-forming agent, such as starch, ethylcellulose, or sodium alginate) applied to the wrapping material 16, and that band circumscribes the cigarette rod in a direction transverse to the longitudinal axis of the cigarette. That is, the band 22 provides a cross-directional region relative to the longitudinal axis of the cigarette. The band 22 can be printed on the inner surface of the wrapping material (i.e., facing the smokable filler material), or less preferably, on the outer surface of the wrapping material. Although the cigarette can possess a wrapping material having one optional band, the cigarette also can possess wrapping material having further optional spaced bands numbering two, three, or more.

At one end of the tobacco rod 12 is the lighting end 18, and at the mouth end 20 is positioned a filter element 26. The filter element 26 positioned adjacent one end of the tobacco rod 12 such that the filter element and tobacco rod are axially aligned in an end-to-end relationship, preferably abutting one another. Filter element 26 may have a generally cylindrical shape, and the diameter thereof may be essentially equal to the diameter of the tobacco rod. The ends of the filter element 26 permit the passage of air and smoke therethrough. The filter element 26 is circumscribed along its outer circumference or longitudinal periphery by a layer of outer plug wrap 28. In a multi-segment filter embodiment, the outer plug wrap 28 overlies each of the segments so as to provide a combined, multi-segment filter element.

The filter element 26 is attached to the tobacco rod 12 using tipping material (not pictured) that circumscribes both the entire length of the filter element 26 and an adjacent region of the tobacco rod 12. Examples of tipping materials are described, for example, in U.S. Pat. No. 7,789,089 to Dube et al., and in U.S. Pat. App. Publ. Nos. 2007/0215167 to Crooks et al., 2010/0108081 to Joyce et al., 2010/0108084 to Norman et al., and 2013/0167849 to Ademe et al.; and PCT Pat. App. Pub. No. 2013/160671 to Dittrich et al., each of which is incorporated by reference herein. The inner surface of the tipping material is fixedly secured to the outer surface of the plug wrap 28 and the outer surface of the wrapping material 16 of the tobacco rod, using a suitable adhesive; and hence, the filter element and the tobacco rod are connected to one another.

A ventilated or air diluted smoking article can be provided with an optional air dilution means, such as a series of perforations 30, each of which extend through the tipping material and plug wrap 28. The optional perforations 30, shown in FIG. 1, can be made by various techniques known to those of ordinary skill in the art, such as laser perforation techniques. Alternatively, so-called off-line air dilution techniques can be used (e.g., through the use of porous paper plug wrap and pre-perforated tipping paper).

For cigarettes that are air diluted or ventilated, the amount or degree of air dilution or ventilation can vary. Frequently, the amount of air dilution for an air diluted cigarette is greater than about 10 percent, generally is greater than about 20 percent, often is greater than about 30 percent, and sometimes is greater than about 40 percent. Typically, the upper level for air dilution for an air diluted cigarette is less than about 80 percent, and often is less than about 70 percent. As used herein, the term “air dilution” is the ratio (expressed as a percentage) of the volume of air drawn through the air dilution means to the total volume and air and smoke drawn through the cigarette and exiting the extreme mouth end portion of the cigarette. Various types of cigarette papers are disclosed and referenced, for example, in U.S. Pat. No. 5,220,930 to Gentry, herein incorporated by reference in its entirety.

During use, the smoker lights the lighting end 18 of the cigarette 10 using a match or cigarette lighter. As such, the smokable material 12 begins to burn. The mouth end 20 of the cigarette 10 is placed in the lips of the smoker. Thermal decomposition products (e.g., components of tobacco smoke) generated by the burning smokable material 12 are drawn through the cigarette 10, through the filter element 26, and into the mouth of the smoker. Following use of the cigarette 10, the filter element 26 and any residual portion of the tobacco rod 12 can be discarded.

As illustrated in FIGS. 2 and 3, for example, the filter element of the invention typically comprises one or more longitudinally-extending rods or segments. Each rod or segment can have varying properties and may include various materials capable of filtration or adsorption of particulate matter and/or vapor phase compounds. Typically, the filter element of the invention includes 1 to 6 segments, frequently 2 to 4 segments. In one preferred embodiment, the filter element includes a mouth end segment and a tobacco end segment. Typical rod sizes range in length from about 40 mm to about 140 mm, and from about 16 mm to about 28 mm in circumference.

The production of multi-segment filter rods can be carried out using the types of rod-forming units that traditionally have been employed to provide multi-segment cigarette filter components. Multi-segment cigarette filter rods can be manufactured using a cigarette filter rod making device available under the brand name Mulfi from Hauni-Werke Korber & Co. KG of Hamburg, Germany. Representative types of filter designs and components, including representative types of segmented cigarette filters, are set forth in U.S. Pat. No. 4,920,990 to Lawrence et al.; U.S. Pat. No. 5,012,829 to Thesing et al.; U.S. Pat. No. 5,025,814 to Raker; U.S. Pat. No. 5,074,320 to Jones et al.; U.S. Pat. No. 5,105,838 to White et al.; U.S. Pat. No. 5,271,419 to Arzonico et al.; U.S. Pat. No. 5,360,023 to Blakley et al.; U.S. Pat. No. 5,396,909 to Gentry et al.; and U.S. Pat. No. 5,718,250 to Banerjee et al; US Pat. Appl. Pub. Nos. 2002/0166563 to Jupe et al., 2004/0261807 to Dube et al.; 2005/0066981 to Crooks et al.; 2006/0090769 to Woodson; 2006/0124142 to Zhang et al.; 2006/0144412 to Mishra et al., 2006/0157070 to Belcastro et al.; and 2007/0056600 to Coleman, III et al.; PCT Publication No. WO 03/009711 to Kim; PCT Publication No. WO 03/047836 to Xue et al.; all of which are incorporated herein by reference.

Multi-segment filter elements typically are provided from so-called “six-up” filter rods, “four-up” filter rods and “two-up” filter rods that are of the general format and configuration conventionally used for the manufacture of filtered cigarettes can be handled using conventional-type or suitably modified cigarette rod handling devices, such as tipping devices available as Lab MAX, MAX, MAX S or MAX 80 from Hauni-Werke Korber & Co. KG. See, for example, the types of devices set forth in U.S. Pat. No. 3,308,600 to Erdmann et al.; U.S. Pat. No. 4,281,670 to Heitmann et al.; U.S. Pat. No. 4,280,187 to Reuland et al.; U.S. Pat. No. 4,850,301 to Greene, Jr. et al.; and U.S. Pat. No. 6,229,115 to Vos et al.; and US Patent Application Publication Nos. 2005/0103355 to Holmes, 2005/1094014 to Read, Jr., and 2006/0169295 to Draghetti, each of which is incorporated herein by reference.

An exemplary multi-segment filter element 200 configuration is shown in FIG. 3; the filter including a first filter segment 205 positioned adjacent one end of the tobacco rod 12 (see, e.g., FIG. 1). The first filter segment 205 can include filter material 212 (e.g., cellulose acetate tow comprising esterified tobacco pulp). Filter element 200 also possesses a second filter segment 210 longitudinally disposed relative to the first segment 205 and positioned at the extreme mouth end of the cigarette 10. The second filter segment 210 includes filter material 214. The filter material 214 of the second filter segment 210 can be the same or different from the filter material 212 of the first filter segment 205. For example, the first filter material 212 can be a cellulose acetate tow comprising esterified tobacco pulp (or a pleated paper material made from tobacco pulp) and the second filter material 214 can also be a cellulose acetate tow comprising esterified tobacco pulp (or a pleated paper material made from tobacco pulp), or the second filter material 214 can be a cellulose acetate tow that does not include tobacco pulp.

The filter element could also include a cavity formed between two filter material segments (not pictured). Still further, the filter segment comprising tobacco pulp can be more centrally located within the filter element with one or more filter segments that do not contain tobacco pulp on each side. Alternatively, all filter segments could include tobacco pulp. In some embodiments, a filter element can comprise a first filter segment comprising a first filter material in the form of a paper comprising pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species and a second filter segment comprising a second filter material in the form of a fibrous tow comprising pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species. Other filter element arrangements could be used without departing from the invention.

In some embodiments, a plurality of degradable particles can be dispersed within the either or all of filter materials 212, 214. If desired, the filter element can also incorporate other components that have the ability to alter the properties of the mainstream smoke that passes throughout the filter element, such as adsorbent materials or flavorants. Exemplary adsorbent materials include activated carbon and ion exchange resins, and exemplary flavorants include flavorant-containing capsules and solid botanical additives such as peppermint or spearmint leaves or other plant-based flavorants in particulate form. See, for example, U.S. Pat. No. 6,041,790 to Smith et al. and US Pat. Application Publication Nos. 2004/0237984 to Figlar et al.; 2005/0268925 to Schluter et al.; 2006/0130861 to Luan et al.; and 2006/0174899 to Luan et al., which are incorporated herein by reference.

The dimensions of a representative cigarette 10 can vary. Preferred cigarettes are rod-shaped, and can have diameters of about 7.5 mm (e.g., circumferences of about 20 mm to about 27 mm, often about 22.5 mm to about 25 mm); and can have total lengths of about 70 mm to about 120 mm, often about 80 mm to about 100 mm. The length of the filter element 30 can vary. Typical filter elements can have total lengths of about 15 mm to about 40 mm, often about 20 mm to about 35 mm. For a typical dual-segment filter element, the downstream or mouth end filter segment often has a length of about 10 mm to about 20 mm; and the upstream or tobacco rod end filter segment often has a length of about 10 mm to about 20 mm.

Various types of cigarette components, including tobacco types, tobacco blends, top dressing and casing materials, blend packing densities and types of paper wrapping materials for tobacco rods, can be employed. See, for example, the various representative types of cigarette components, as well as the various cigarette designs, formats, configurations and characteristics, that are set forth in Johnson, Development of Cigarette Components to Meet Industry Needs, 52^(nd) T.S.R.C. (September, 1998); U.S. Pat. No. 5,101,839 to Jakob et al.; U.S. Pat. No. 5,159,944 to Arzonico et al.; U.S. Pat. No. 5,220,930 to Gentry and U.S. Pat. No. 6,779,530 to Kraker; US Patent Publication Nos. 2005/0016556 to Ashcraft et al.; 2005/0066986 to Nestor et al.; 2005/0076929 to Fitzgerald et al.; 2006/0272655 to Thomas et al.; 2007/0056600 to Coleman, III et al.; and 2007/0246055 to Oglesby, each of which is incorporated herein by reference. Most preferably, the entire smokable rod is composed of smokable material (e.g., tobacco cut filler) and a layer of circumscribing outer wrapping material.

Filter elements of the present invention can be incorporated within the types of cigarettes set forth in U.S. Pat. No. 4,756,318 to Clearman et al.; U.S. Pat. No. 4,714,082 to Banerjee et al.; U.S. Pat. No. 4,771,795 to White et al.; U.S. Pat. No. 4,793,365 to Sensabaugh et al.; U.S. Pat. No. 4,989,619 to Clearman et al.; U.S. Pat. No. 4,917,128 to Clearman et al.; U.S. Pat. No. 4,961,438 to Korte; U.S. Pat. No. 4,966,171 to Serrano et al.; U.S. Pat. No. 4,969,476 to Bale et al.; U.S. Pat. No. 4,991,606 to Serrano et al.; U.S. Pat. No. 5,020,548 to Farrier et al.; U.S. Pat. No. 5,027,836 to Shannon et al.; U.S. Pat. No. 5,033,483 to Clearman et al.; U.S. Pat. No. 5,040,551 to Schlatter et al.; U.S. Pat. No. 5,050,621 to Creighton et al.; U.S. Pat. No. 5,052,413 to Baker et al.; U.S. Pat. No. 5,065,776 to Lawson; U.S. Pat. No. 5,076,296 to Nystrom et al.; U.S. Pat. No. 5,076,297 to Farrier et al.; U.S. Pat. No. 5,099,861 to Clearman et al.; U.S. Pat. No. 5,105,835 to Drewett et al.; U.S. Pat. No. 5,105,837 to Barnes et al.; U.S. Pat. No. 5,115,820 to Hauser et al.; U.S. Pat. No. 5,148,821 to Best et al.; U.S. Pat. No. 5,159,940 to Hayward et al.; U.S. Pat. No. 5,178,167 to Riggs et al.; U.S. Pat. No. 5,183,062 to Clearman et al.; U.S. Pat. No. 5,211,684 to Shannon et al.; U.S. Pat. No. 5,240,014 to Deevi et al.; U.S. Pat. No. 5,240,016 to Nichols et al.; U.S. Pat. No. 5,345,955 to Clearman et al.; U.S. Pat. No. 5,396,911 to Casey, III et al.; U.S. Pat. No. 5,551,451 to Riggs et al.; U.S. Pat. No. 5,595,577 to Bensalem et al.; U.S. Pat. No. 5,727,571 to Meiring et al.; U.S. Pat. No. 5,819,751 to Barnes et al.; U.S. Pat. No. 6,089,857 to Matsuura et al.; U.S. Pat. No. 6,095,152 to Beven et al; and U.S. Pat. No. 6,578,584 to Beven; which are incorporated herein by reference. Still further, filter elements of the present invention can be incorporated within the types of cigarettes that have been commercially marketed under the brand names “Premier” and “Eclipse” by R. J. Reynolds Tobacco Company. See, for example, those types of cigarettes described in Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco, R. J. Reynolds Tobacco Company Monograph (1988) and Inhalation Toxicology, 12:5, p. 1-58 (2000); which are incorporated herein by reference.

Cigarette rods typically are manufactured using a cigarette making machine, such as a conventional automated cigarette rod making machine. Exemplary cigarette rod making machines are of the type commercially available from Molins PLC or Hauni-Werke Korber & Co. KG. For example, cigarette rod making machines of the type known as MIA (commercially available from Molins PLC) or PROTOS (commercially available from Hauni-Werke Korber & Co. KG) can be employed. A description of a PROTOS cigarette making machine is provided in U.S. Pat. No. 4,474,190 to Brand, at col. 5, line 48 through col. 8, line 3, which is incorporated herein by reference. Types of equipment suitable for the manufacture of cigarettes also are set forth in U.S. Pat. No. 4,781,203 to La Hue; U.S. Pat. No. 4,844,100 to Holznagel; U.S. Pat. No. 5,131,416 to Gentry; U.S. Pat. No. 5,156,169 to Holmes et al.; U.S. Pat. No. 5,191,906 to Myracle, Jr. et al.; U.S. Pat. No. 6,647,870 to Blau et al.; U.S. Pat. No. 6,848,449 to Kitao et al.; and U.S. Pat. No. 6,904,917 to Kitao et al.; and US Patent Application Publication Nos. 2003/0145866 to Hartman; 2004/0129281 to Hancock et al.; 2005/0039764 to Barnes et al.; and 2005/0076929 to Fitzgerald et al.; each of which is incorporated herein by reference.

The components and operation of conventional automated cigarette making machines will be readily apparent to those skilled in the art of cigarette making machinery design and operation. For example, descriptions of the components and operation of several types of chimneys, tobacco filler supply equipment, suction conveyor systems and garniture systems are set forth in U.S. Pat. No. 3,288,147 to Molins et al.; U.S. Pat. No. 3,915,176 to Heitmann et al.; U.S. Pat. No. 4,291,713 to Frank; U.S. Pat. No. 4,574,816 to Rudszinat; U.S. Pat. No. 4,736,754 to Heitmann et al. U.S. Pat. No. 4,878,506 to Pinck et al.; U.S. Pat. No. 5,060,665 to Heitmann; U.S. Pat. No. 5,012,823 to Keritsis et al. and U.S. Pat. No. 6,360,751 to Fagg et al.; and US Patent Publication No. 2003/0136419 to Muller; each of which is incorporated herein by reference. The automated cigarette making machines of the type set forth herein provide a formed continuous cigarette rod or smokable rod that can be subdivided into formed smokable rods of desired lengths.

Preferred cigarettes of the present invention exhibit desirable resistance to draw. For example, an exemplary cigarette exhibits a pressure drop of between about 50 and about 200 mm water pressure drop at 17.5 cc/sec. air flow. Preferred cigarettes exhibit pressure drop values of between about 60 mm and about 180, more preferably between about 70 mm to about 150 mm, water pressure drop at 17.5 cc/sec. air flow. Typically, pressure drop values of cigarettes are measured using a Filtrona Cigarette Test Station (CTS Series) available from Filtrona Instruments and Automation Ltd.

Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing description; and it will be apparent to those skilled in the art that variations and modifications of the present invention can be made without departing from the scope or spirit of the invention. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 

What is claimed is:
 1. A filter material adapted for use as a filter element of a smoking article, comprising at least 10 dry weight percent of cellulosic pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species, wherein the filter material is in the form of a paper comprising the cellulosic pulp or a fibrous tow comprising the cellulosic pulp in esterified form.
 2. The filter material of claim 1, wherein the filter material is in the form of a paper that is pleated to form a rod-like element.
 3. The filter material of claim 2, wherein the web of sheet-like material has a basis weight of about 20 gsm to about 90 gsm.
 4. The filter material of claim 1, wherein the filter material comprises at least 20 dry weight percent of cellulosic pulp derived from stalks, roots, or a combination thereof of a plant of the Nicotiana species.
 5. A filter element for a smoking article comprising one or more segments of a filter material according to claim
 1. 6. A cigarette comprising a tobacco rod having a smokable filler material contained within a circumscribing wrapping material and a filter element connected to the tobacco rod at one end of the tobacco rod, said filter element comprising at least one segment of a filter material according to claim
 1. 7. A method for formation of a filter element of a smoking article, the method comprising: i) pulping a tobacco input comprising stalks, roots, or a combination thereof of a plant of the Nicotiana species to form a cellulosic pulp; ii) forming a web of sheet-like material comprising the cellulosic pulp; and iii) pleating the web of sheet-like material to form a rod-like element suitable for use in a filter element.
 8. The method of claim 7, wherein the web of sheet-like material has a basis weight of about 20 gsm to about 90 gsm.
 9. The method of claim 7, wherein the web of sheet-like material comprises at least 10 dry weight percent of the cellulosic pulp.
 10. The method of claim 7, wherein the web of sheet-like material comprises at least 20 dry weight percent of the cellulosic pulp.
 11. The method of claim 7, wherein the rod-like element is adapted for use as a filter element in a smoking article.
 12. A method for formation of a filter element of a smoking article, the method comprising: i) pulping a tobacco input comprising stalks, roots, or a combination thereof of a plant of the Nicotiana species to form a cellulosic pulp; ii) esterifying the cellulosic pulp to produce cellulose acetate; iii) dissolving the cellulose acetate in a solvent to form a cellulose acetate dope; iv) spinning the cellulose acetate dope into a plurality of filaments; and v) collecting, drying and crimping the plurality of filaments to form a tow material suitable for use in a filter element, the tow material comprising at least 10 dry weight percent of cellulose acetate filaments made from the cellulosic pulp.
 13. The method of claim 12, further comprising blending the tow material with ethyl cellulose fibers, cellulose acetate-lignin blended fibers, or a combination thereof to form a biodegradable blend of filter tow material suitable for use in a filter element.
 14. The method of claim 12, wherein the tow material comprising at least 20 dry weight percent of cellulose acetate filaments made from the cellulosic pulp. 